Recognition by degree prime-power graph and order of some characteristically simple groups

In this paper, by the order of a group and triviality of Op(G) for some prime p, we give a new characterization for some characteristically simple groups. In fact, we prove that if p ∈ {5, 17, 23, 37, 47, 73} and n 6 p, where n is a natural number, then G ∼= PSL(2, p) n if and only if |G| = |PSL(2, p)| n and Op(G) = 1. Recently in [Qin, Yan, Shum and Chen, Comm. Algebra, 2019], the degree primepower graph of a finite group have been introduced and it is proved that the Mathieu groups are uniquely determined by their degree prime-power graphs and orders. As a consequence of our results, we show that PSL(2, p) n, where p ∈ {5, 17, 23, 37, 47, 73} and n 6 p are uniquely determined by their degree prime-power graphs and orders.